The concept of “roaming” in wireless telephone networks is well known. It allows a wireless telecommunications network service subscriber with a mobile device (e.g., a cell phone) to travel into the geographical territory of a different wireless network while still being able to use the mobile device. The mobile device registers itself with the visited network and the subscriber is subsequently enabled to use the mobile device (which is considered to have “roamed” into the visited network) essentially as if it were still located within the geographical boundaries of the user's own “home” network. The home network and the visiting network will typically have explicit agreements which support the ability for each other's subscribers to roam into the other network's area. And in most cases, the user is provided with the same full functionality as if he or she remained in the territory of the home network—partly as a result of using the same physical device and partly as a result of functionality explicitly provided by the visiting network.
In particular, that is, an inherent advantage to the concept of wireless “roaming” is that the user typically not only has the full functionality that he or she normally has, but the user's telecommunications “environment” appears no different when roaming than when he or she is using his or her mobile device within its home area. Most importantly, the user's cellular phone number travels with him or her (for purposes of incoming calls), since that number is specifically associated with the physical cell phone itself. Of course, none of this seems at all “unnatural” to us, because the mobile terminal (e.g., the cell phone) is in fact the same physical device that is merely being carried from place to place. And it is common to mentally associate the functionality, features and telephone number of our wireless telecommunications “environment” with the physical device itself, even though for many of these features (e.g., voice messaging), the functionality is actually provided within the telecommunications network and not within the cell phone itself.
On the other hand, whenever we use a wireline telephone at a location other than our home or office, it is almost invariably not the same physical device, and therefore it is not “expected” that it will behave identically to our “normal” telephone at our home or office. We fully accept, for example, that the dial tone may sound different, that our preprogrammed “speed dials” will not be available, and that we may not have available to us the same special feature functionality such as conference calling, call transfers, placing calls on hold and multiple line capability. And again, most significantly for the purpose of receiving incoming calls, we accept that we are “located” at a different phone number, although conventional call forwarding techniques can partially alleviate this problem.
Quite often, for example, a company employee (generically, an “associate” of an “enterprise”) who regularly works in a conventional office environment, needs to travel or temporarily relocate to another location for business purposes. When “at home” in his or her office, the telecommunications system the employee will use will most typically comprise either a conventional PBX (Public Branch Exchange) system or a conventional Centrex system. (PBX and Centrex systems are fully familiar to those of ordinary skill in the art.) As such, the “environment” (e.g., the features and functionality) available to the employee will be dictated by the particular PBX or Centrex system in combination with the physical telephone in his or her office. Moreover, the phone number at the employee's office will be fixed—typically either a direct (e.g., 10-digit) phone number for Centrex systems, or a (10-digit) phone number plus an extension for PBX systems.
However, when the employee is away from his or her office, being physically situated in a hotel room, in a public phone booth, or in another office in, for example, another office building, the employee will have to use the telecommunication system available without having the convenience and functionality that he or she has in his or her office. And while conventional call forwarding techniques may in some cases be used to automatically redirect incoming calls from the employee's office phone to the phone at the location where he or she is presently situated, it cannot otherwise recreate the office wireline telecommunications environment. Thus, it would be highly desirable if a wireline telecommunications system could provide for the ability for a telecommunications system user to have the same telecommunications “environment” while using any physical device (e.g., telephone) or, for that matter, any physical telephone line (e.g., “landline”), and to thereby make the device at the user's location appear the same as the user's “home” phone for both incoming and outgoing call functionality. (As used herein, a “home” phone is any wireline or wireless telecommunications device which is used on a regular basis by the user, such as the user's home or office telephone. Also as used herein, the term “telecommunications device,” when used without qualification, is intended to include any device capable of serving as a telecommunications user terminal, including, without limitation, conventional wireline telephones, cellular telephones, Personal Data Assistants or PDAs with telecommunications capability, computers with Internet or other networking capability, etc.)